DESCRIPTION: Injecting drug use has been the main driver of HIV epidemics in many parts of the world. Despite recent scientific breakthroughs, many HIV positive injection drug users (HIV+ IDUs) still faced with significant barriers at multiple levels that prevent them from accessing to and being retained in services. Over the past decade, with support largely from the US's President Emergency Plan for AIDS Relief (PEPFAR), Vietnam has built two parallel treatment systems of outpatient HIV clinics and Methadone Maintenance Therapy (MMT) clinics. However, limited access to and retention in these services by HIV+ IDUs, which are predominantly men, has not maximized the potential effects of the two systems. In the next few years, when PEPFAR reduces its financial support for service delivery, the financial burden will fall upon families and individual patients. In this two-year study, a team of investigators from th Columbia University's Department of Sociomedical Sciences, University of Miami's Center for Family Studies, and Hanoi Medical University's Center for Research and Training on HIV/AIDS are collaborating to investigate ways in which the family, defined broadly to include those who have mutual commitment through enduring relationships, are involved with HIV+ male IDUs, and to explore how family members could support better access to and retention in HIV care and substance abuse treatment. Our specific aims are: (1) Identify strategies to recruit family members of HIV+ male IDU by conducting in-depth interviews with 10 physicians or counselors/nurses of MMT and HIV clinics, 5 peer educators of Hanoi Provincial AIDS Center, and 30 men (20 from MMT and HIV clinics, and 10 non-MMT, non-ART or out-of-treatment IDUs); (2) Assess family networks, family involvement, and various health and social factors theorized to be associated with family involvement with HIV+ male IDUs by conducting family network mapping with 300 men (100 from MMT clinics, 100 from HIV clinics and 100 out-of-treatment IDUs) and a cross-sectional survey with these men as well as at least 300 family members who are recruited by the index men. (3) Investigate ways in which family members are involved with HIV+ male IDU, and how the family could become recovery capital or impediments for engaging in substance use treatment and HIV medical care by conducting in-depth interviews with 30 men (10 from each of the above settings) and 30 family members who are parts of the cross-sectional survey. Study results will guide the development of new and innovative strategies to improve HIV and substance abuse outcomes for male IDUs in Vietnam and beyond.